1. Technical Field
Embodiments of the invention relate generally to electronic devices such as power converters. Other embodiments relate to power converter control systems.
2. Discussion of Art
In the mining industry, large off-highway vehicles (“OHVs”) are used to haul heavy payloads excavated from open pit mines. OHVs usually employ electrically motorized wheels for propelling or retarding the vehicle in an energy efficient manner. In particular, OHVs typically utilize a large horsepower diesel engine in conjunction with an alternator, a main traction inverter, and a pair of wheel drive assemblies housed within the rear tires of the vehicle. The diesel engine is directly associated with the alternator such that the diesel engine drives the alternator. The alternator powers a main traction power converter, in which power semiconductor devices commutate the alternator output current to provide electrical power having a controlled voltage and frequency for electric drive motors of the two wheel drive assemblies.
Power converters suitable for use with OHV include, for example, an isolated bidirectional H-bridge converter that features two full semiconductor bridges connected through a power transformer. Such a converter can transfer power in both directions with voltages at primary and secondary sides varying within a range.
An isolated H-bridge converter, or other power electronics, may include power elements, e.g., switchable semiconductor devices, such as insulated gate bipolar transistors, (IGBTs), that are switched on and off by drive circuitry in an alternating fashion to produce an output AC waveform. Other types of power elements may also be used in the H-bridge circuit such as power BJT transistors, power MOSFETs, integrated gate commutated thyristors (IGCT), gate turn-off thyristors (GTO), or any other device controllable semiconductor switched by a low power signal (gate signal).
Typically, each power element within a power converter is switched on and off by gate voltage supplied from a gate drive unit. The gate drive unit typically is controlled via a wired connection from a control unit. The control units, however, may be physically remote from the gate drive unit. Moreover, OHVs are typically used under challenging environmental conditions that impose risks of physical damage to wired connections such as fiber optic or electrical cabling that may be used for routing signals from a control unit to a gate drive unit. Other types of equipment including power converters, such as for example industrial robots, may also be exposed to challenging environmental conditions.
Accordingly, it may be desirable to provide power converter control systems that differ from systems currently available.